a. Field of Invention
The invention relates generally to hinges for vehicle closure members, and more particularly, to hinges that facilitate removal and installation of vehicle doors for expediting the vehicle assembly process.
b. Description of Related Art
As is known in the art, removing vehicle doors from a vehicle body during a particular segment of a vehicle assembly process, also known as a “doors off” technique, helps achieve automotive manufacturing efficiency. As opposed to keeping the doors on the vehicle body after initial attachment, this doors off technique provides increased access through door opening areas for facilitating installation of vehicle components, such as vehicle seats. After the doors are removed from the vehicle body on the primary assembly line, the doors may be separately outfitted in an off-line door assembly process. Window systems, door latches, door handles, and trim panels are a few of the exemplary components that can be installed on vehicle doors while removed from the vehicle body. Following this stage, the doors may be reattached to the vehicle body.
Many vehicle door-to-body hinges exist that attempt to make attaching, removing, and reattaching doors to the vehicle body as efficient as possible. In general, fewer parts that need to be removed and reattached correlates to better assembly efficiency. Some take-apart hinges allow a door to be detached from the vehicle body after one or more pins, bolts, etc. are removed from the hinge. The door is then lifted off the vehicle body for separate subassembly. Current lift-off hinges are typically made from profile stock or forgings, and are thus generally more costly than stamped hinges. Such profile and forged lift-off hinges cannot cost effectively package a locating pin on a body side bracket of the hinge to enable certain low investment door hang concepts. Conversely, current stamped hinges which incorporate a lift off feature compromise hinge strength or dimensional integrity.
Exemplary lift-off vehicle door hinges are disclosed in U.S. Pat. Nos. 4,765,025 and 4,766,643 to Salazar, respectively (Salazar '025 and Salazar '643). Referring to FIGS. 1-3 of Salazar '025 and Salazar '643, whereas the patents disclose the use of cost effective stamped brackets on the upper and lower hinges, the assemblies use a considerable number of fasteners to attach body mounting plate (20), door mounting plate (22), and door (14) to one another and to vehicle (10). Even if only one or two fasteners are used to hold the door in place until final assembly, driving a surplus of fasteners is detrimental to assembly time and component cost. One inefficiency is evidenced through the use of two pivot pins (24, 26) instead of one, which can add assembly and manufacturing time, and component cost.
In another exemplary stamped hinge assembly, U.S. Pat. No. 4,881,298 to Turnbull teaches a “separable door hinge” that has intertwining leaves, flanges, and tabs for maintaining the door in a fixed vertical position. One drawback to this separable door hinge is in its design to hold the door in a fixed position in relation to the height of the vehicle body. Referring to FIG. 1 of Turnbull, since the intertwining projections mentioned above, such as lower flange (52) rotating between tab (40) and lower flange (24), are not clamped by a traditional fastener, as shown in FIG. 2, relative movement of flanges (24, 52) during opening and closing of the door causes the intertwining projections to scrape one another. If the components have any free-play, even minimal vertical movement of the door can cause unnecessary fatigue on related components such as the striker member, the door latch, the periphery of the door opening, and the hinge components themselves. If the components are assembled too tightly, friction present during relative movement of the components can cause unnecessary fatigue on hinge components and undesirable noise and vibrations. Yet further, when a door is removed from the vehicle body, the main pivot is not kept intact.
Such deficiencies in existing technology make it desirable to provide a durable and robust door-to-body hinge that remains intact when the door is lifted off the vehicle body for separate subassembly. It is further desirable to provide a hinge that uses cost effective stamped components, and minimal joints for attaching, removing, and reattaching a door to a vehicle body.